1. Field of the Invention
The present invention concerns a power supply which can be mounted on a pole, such as a pole for hanging intravenous fluids, and other equipment. More particularly, it concerns a power supply which controls total patient leakage current to the low levels required by one or more national or international standards applicable to this type of medical electrical equipment.
2. Background
There are many industry standards governing medical electrical equipment, such as IV pumps, patient monitors, and the like, that are used in medical and clinical settings. The international industry standard IEC 60601-1 requires that maximum patient touch current (the current flowing between the patient and ground) from all such devices does not exceed 100 μA (microamps). Underwriter's Laboratories has established standard UL 60601-1, which has similar requirements and serves as a de facto industry standard in the U.S. and Canada. Generally speaking, hospitals in the U.S. and Canada will not allow medical electrical equipment to be used unless they meet UL standards. A maximum patient touch current of 100 μA is difficult to achieve using normal power strips and one conventional solution is to have a large isolation transformer in a box sitting on the floor near the wall outlet. Various medical electrical equipment may then be plugged into this box. This achieves the requirement to control the patient touch current. However, the box is typically near the wall and running multiple cables from the various medical electrical equipment devices to the box is cumbersome. Furthermore, many cables that come with their respective devices are not sufficiently long to allow this, requiring extension cords, and further increasing the patient leakage current and creating potential trip hazards.
Oftentimes, such items of medical electrical equipment are mounted on an Intravenous (IV) pole, which typically is supported by wheeled legs, to facilitate positioning and transport. Current state-of-the art power supplies, such as the AIV POWERMATE™, marketed by American IV Products, Inc. dba AIV, Inc. of Harmans, Md., U.S.A., may be mounted on such an IV pole via a mounting assembly formed on the backside of the unit. The various medical electrical equipment mounted on the IV pole may then be plugged into this power supply. However, this would not meet the IEC 60601-1 patient leakage current industry standard.